<h3>Step 1</h3>
<p>Drag the grid (left mouse button) so that it appears to lie flush against
the surface in an image.  The surface is outlined with a red shape.  When you
are done, the blue arrow should appear to point away from the surface.</p>

<p>Please align the grid (right mouse button) so that it is parallel with other
lines in the photograph.</p>

<h3>Step 2</h3>
<p>On the right, you will see a distorted version of the shape.  This is what
the shape looks like if you are viewing it from a top-down view.  If the
thumbtack is correct, then this distorted shape should appear to face forward.</p>

<p>Please rotate the shape by dragging with the right mouse button so that any
patterns in the shape are aligned vertically.  Adjusting the orientation should
also become easier when the shape is aligned.</p>

<p>For example, if there is a tile pattern in the shape, the tiles should be
parallel in the right image.  If it is a square in the scene, it should appear
as a square in the right image.  The outline of the shape on the right is not
important; the texture and patterns inside is what matters.</p>

<h3>Adjusting the result</h3>

<p>If dragging moves the shape too fast, click the &quot;Fine adjustment&quot;
button.  You may also zoom with the &quot;Zoom in&quot; button.</b>

{% include "mturk/examples.html" %}

<br/>
<h2>Why are we doing this?</h2>

<p>We are trying to understand the 3D structure of photographs.  These
thumbtack orientations allow us to <i>rectify</i> shapes so that they appear to
face the camera. This experiment is part of ongoing research at Cornell University.  Thanks
for participating!</p>
